Compensation reservoir for a cooling circuit of an internal combustion engine

ABSTRACT

A compensating tank for a cooling circuit of an internal combustion engine has at least one inflow connection and one outflow connection, both of which are connected with the cooling circuit, a chamber system formed in the tank to receive the coolant, such that the individual chambers are at least partially interconnected via openings, and a coolant pipe connected with the inflow connection discharging into one of the chambers in which an impact element is provided for the inflowing coolant. The impact element is configured as a curved guiding wall along which the inflowing coolant is specifically guided. This inhibits, among other things, foaming of the coolant flowing into the compensating tank.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to a compensating tank for a cooling circuit of an internal combustion engine.

German Laid Open Document DE 100 21 180 A1 discloses a compensating tank of a cooling circuit of an internal combustion engine in which means are provided to reduce foaming of the coolant introduced into the compensating tank. For this purpose, the coolant is introduced via a coolant pipe into a chamber of the tank where it initially meets a U-shaped trough provided in the chamber through which the coolant can drain into the coolant reservoir after overcoming the overflow edge of the trough. The coolant flowing out of the coolant pipe first strikes an end face of the trough, however, so that there is a risk of additional foam formation. German Laid Open Document DE 40 35 284 A1 describes a compensating tank in which a coolant pipe discharges into the compensating tank below the liquid level.

Thus, an object of the invention is to provide means in a coolant compensating tank to slow down the coolant enriched with gas bubbles that exits from the coolant pipes such that foam formation in the compensating tank is largely avoided in all possible driving situations of the motor vehicle (e.g., driving uphill or downhill or driving curves with high lateral acceleration). At the same time, the coolant flowing into the compensating tank should be deaerated before it is fed back into the actual cooling circuit of the internal combustion engine.

This object is attained according to the invention.

The arrangement of the coolant pipes in the compensating tank is adjusted to the liquid level in the compensating tank so that, normally, the coolant pipes discharge at or below the liquid level. This prevents foaming essentially because the higher viscosity of the liquid in the compensating tank effectively decreases the kinetic energy of the inflowing water/gas mixture. Particularly during uphill or downhill driving, however, it is no longer ensured that the coolant exiting from the coolant pipes still discharges below or at the liquid level. In this case the curved guiding walls provided in the compensating tank ensure that the kinetic energy of the inflowing coolant is continuously decreased such that foaming is largely avoided even in these driving situations.

Other advantages and advantageous embodiments of the invention are set forth in the dependent claims and the description.

A particularly effective introduction of the inflowing liquid results if the coolant pipe discharging into the chamber with the guiding wall and its outlet opening are oriented in such a way that the outflowing coolant strikes the curved guiding wall approximately tangentially.

The compensating tank, which is advantageously made of plastic, consists of an upper and a lower shell. The guiding wall and the coolant pipe are integrated in the upper shell.

A chamber system is likewise formed in the upper shell, and the walls of the individual chambers are interconnected via openings to equalize the pressure. The coolant pipe is guided through some of the openings; these openings are dimensioned in such a way that they are simultaneously available as chamber-connecting openings.

To give the coolant flowing into the compensating tank sufficient time for defoaming, the exits of the coolant from the coolant pipe as well as the guiding wall are arranged in the rearmost chamber row-relative to the outflow connection.

In the upper shell of the compensating tank, two coolant pipes discharging into the chamber system are advantageously provided. The first coolant pipe communicates with a radiator and the second coolant pipe communicates with the water jacket of the cylinder head of the internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described in greater detail, by way of example, with reference to the drawing in which:

FIG. 1 is a longitudinal section of a compensating tank,

FIG. 2 is a cross section of a compensating tank,

FIG. 3 is an interior view of an upper shell of the compensating tank, and

FIG. 4 is an interior view of a lower shell of a compensating tank.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

The compensating tank 2 integrated into the cooling circuit of an internal combustion engine has an upper shell 4 and a lower shell 6, which are joined, for example, by vibration welding. The coolant flows into the compensating tank 2 through two pipes integrated in the upper shell 4, hereinafter referred to as coolant pipes 8 and 10. The return flow or outlet 12 is formed in the lower shell 6. Both the upper and the lower shell 4, 6, have a chamber system, which will now be described in greater detail. In the upper shell 4, in the present example, there are twelve chambers 14 a to 14 l, which are formed by transverse and longitudinal walls 15 a to 15 i and 16 a to 16 h rising from the bottom of the upper shell 4. The two coolant pipes 8 and 10 introduced into the upper shell 4 are guided through openings 17 a to 17 c and, respectively, 17 d to 17 f made in the transverse walls 15 a to 15 c and, respectively, 15 g to 15 i up to the two rearmost chambers 14 d and 141. The openings 17 a to 17 c and 17 d to 17 f are larger than the outside diameters of the coolant pipes 8 and 10, such that the chambers 14 a to 14 d and 14 i to 14 l are interconnected via the openings 17 a to 17 c and 17 d to 17 f. The two coolant pipes 8, 10 are fixed in the upper shell 4 by plastic brackets 18 a to 18 e formed out of the bottom of the upper shell 4. In addition to the openings 17 a to 17 c and 17 d to 17 f, openings 20 a to 20 e connecting the chambers 14 b to 141 are provided at the crossing points 19 a to 19 e of the transverse and longitudinal walls 15 a to 15 i and 16 a to 16 h.

Curved guiding walls 21 and 22 are provided in the two chambers 14 d and 141. Their function is described in greater detail below in connection with the coolant exiting from the coolant pipes 8, 10. The two guiding walls 21, 22, analogous to the fixation brackets 18 a to 18 e, are formed from the bottom of the upper shell 4 as integral components and are further anchored to the walls of the chamber system. The upper shell 4 has an opening 24 provided with an internal thread, which receives a relief and vacuum valve (not depicted).

Analogous to the chamber system provided in the upper shell 4, the lower shell 6 is likewise divided into individual chambers 26 a to 261, the size or dimensioning of which essentially corresponds to the chambers 14 a to 141 provided in the upper shell 4. The chambers 26 a to 261 are again divided by corresponding transverse walls 27 a to 27 i and longitudinal walls 28 a to 28 h. Openings 29 a to 29 i and, respectively, 30 a to 30 g are provided in both the transverse walls 27 a to 27 i and in the longitudinal walls 28 a to 28 h (except for 28 b).

It is generally known that the compensating tank 2 is used to cushion or maintain the pressure in the cooling system of the internal combustion engine. A further function of the compensating tank is to ensure deaeration of the cooling system. For this purpose, it has to be ensured that air flowing into the compensating tank 2 together with the coolant through the deaeration lines 8 and 10 remains in the compensating tank 2 and foaming of the coolant is inhibited. The configuration of the interior structure of the compensating tank 2 ensures these functions, which will now be described in greater detail. The coolant pipes 8, 10, which are connected, respectively, with the radiator and the water jacket of the cylinder head of the internal combustion engine, conduct the coolant specifically into the rearmost chambers 14 d and, respectively, 14 l—relative to the outlet 12 provided in the lower shell 6. If the vehicle is in its normal position, i.e., if it is not strongly tilted about its longitudinal and/or transverse axis and if no significant longitudinal or transverse accelerations occur, the position of the coolant pipes 8, 10 relative to the liquid level in the compensating tank 2 is adjusted such that the ends of the coolant pipes 8, 10 discharge at or below the liquid level. This prevents foam formation essentially because the higher viscosity of the liquid in the compensating tank effectively reduces the kinetic energy of the inflowing coolant or the water/gas mixture. The approximately tangential impact of the outflowing coolant on the two curved guiding walls 21, 22 is a further means to reduce the kinetic energy and thereby to reduce foaming.

Particularly during uphill or downhill driving or during acceleration of the vehicle it is no longer ensured, however, that the coolant exiting from the coolant pipes still discharges into the compensating tank 2 below or at the liquid level. In this case, the curved guiding walls 21, 22 provided in the compensating tank 2 ensure that the kinetic energy of the coolant flowing into the two chambers 26 d and 26 l is not reduced abruptly, but gradually as a result of the spiral flow of the coolant, such that foaming is largely avoided in these driving situations as well.

As the arrows indicate in FIG. 4, the coolant is guided through a plurality of chambers through the openings 29, 30 made in the transverse and longitudinal walls 27, 28 before it is fed into the actual cooling circuit of the internal combustion engine via outlet 12. The coolant can deposit foam in each of these chambers because the openings 29, 30 are below the surface of the water. The openings 17 and 20 made in the upper shell 4 ensure that the pressure of the air in the upper shell 4 is equalized.

In addition to providing a coolant defoaming function, the chambers prevent the coolant from sloshing back and forth when the motor vehicle or the engine is at an angle. At the same time, the chamber system contributes to an overall stiffening of the compensating tank.

The horizontal marking ribs 31, 32 shown in Figure serve to indicate the coolant filling level. The marking rib 31 shows the maximum cold filling volume V_(max) and the marking rib 32 the minimum cold filling volume V_(min). 

1-7. (canceled)
 8. A compensating tank for a cooling circuit of an internal combustion engine comprising: at least one inflow connection and at least one outflow connection, both of which are connected to the cooling circuit, a chamber system formed in the tank to receive coolant such that individual chambers are at least partially interconnected via openings, and a coolant pipe connected with the inflow connection discharging into one of the chambers in which an impact element for inflowing coolant is provided, wherein the impact element is configured as a curved guiding wall along which the inflowing coolant is guided.
 9. The compensating tank as claimed in claim 8, wherein the coolant pipe discharging into the one of the chambers, the guiding wall, and an outlet opening are oriented in such a way that the outflowing coolant strikes the guiding wall approximately tangentially.
 10. The compensating tank as claimed in claim 8, wherein the compensating tank is constructed of an upper shell and a lower shell, and wherein the guiding wall and the coolant pipe are integrated into the upper shell.
 11. The compensating tank as claimed in claim 10, wherein walls of the individual chambers have openings in the upper shell through which the coolant pipe is guided, and wherein the openings are dimensioned such that they are simultaneously available as the openings connecting the chambers.
 12. The compensating tank as claimed in claim 8, wherein the guiding wall is arranged in a rearmost chamber row relative to the at least one outflow connection.
 13. The compensating tank as claimed in claim 10, wherein the lower shell is provided with a chamber system such that the chambers are interconnected via openings provided in transverse walls and longitudinal walls.
 14. The compensating tank as claimed in claim 8, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine.
 15. The compensating tank as claimed in claim 9, wherein the compensating tank is constructed of an upper shell and a lower shell, and wherein the guiding wall and the coolant pipe are integrated into the upper shell.
 16. The compensating tank as claimed in claim 15, wherein walls of the individual chambers have openings in the upper shell through which the coolant pipe is guided, and wherein the openings are dimensioned such that they are simultaneously available as the openings connecting the chambers.
 17. The compensating tank as claimed in claim 9, wherein the guiding wall is arranged in a rearmost chamber row relative to the at least one outflow connection.
 18. The compensating tank as claimed in claim 10, wherein the guiding wall is arranged in a rearmost chamber row relative to the at least one outflow connection.
 19. The compensating tank as claimed in claim 11, wherein the guiding wall is arranged in a rearmost chamber row relative to the at least one outflow connection.
 20. The compensating tank as claimed in claim 11, wherein the lower shell is provided with a chamber system such that the chambers are interconnected via openings provided in transverse walls and longitudinal walls.
 21. The compensating tank as claimed in claim 12, wherein the lower shell is provided with a chamber system such that the chambers are interconnected via openings provided in transverse walls and longitudinal walls.
 22. The compensating tank as claimed in claim 9, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine.
 23. The compensating tank as claimed in claim 10, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine.
 24. The compensating tank as claimed in claim 11, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine.
 25. The compensating tank as claimed in claim 12, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine.
 26. The compensating tank as claimed in claim 13, wherein the coolant pipe is one of two coolant pipes that discharge into the chamber system, such that a first of the coolant pipes is connected with a radiator and the second of the coolant pipes is connected with a water jacket of a cylinder head of the internal combustion engine. 